Microsoft has released Server Performance Advisor v1.0 which is a performance diagnostic tool for Windows Server 2003. Please note that this tool does not works with Windows XP or old version of Windows server (NT/2000).
Tool is available for download at: Microsoft web site.
From Microsoft site, “…Service Performance Advisor is a server performance diagnostic tool developed to diagnose root causes of performance problems in a Microsoft Windows Server 2003 operating system, particularly performance problems for Internet Information Services (IIS) 6.0 and the Active Directory directory service. Server Performance Advisor measures the performance and use of resources by your computer to report on the parts that are stressed under workload.
Other server roles include system overview (hot files, hot TCP clients, top CPU consumed), print spooler, context switch data and preliminary File Server trace data.
I find this tool quite valuable while, troubleshooting Windows Server 2003 performance problems.